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G. E. H. MATHES.

METAL CLOCK DIAL.

APPLICATION nu mm. 1920 Patented July 20, 1920.

UNITED STATES PATENT OFFICE.

GUNTHER E. H: MATHES, 0F WATERBURY, CONNECTICUT, ASSIGNOR TO WATERBURY CLOCK 00., OF WATERBURY, CONNECTICUT, A CORPORATION.

METAL CLOCK-DIAL.

Specification of Letters Patent.

Patented July 20, 1920.

To all whom it may concern:

Be it i known that I, GUNTHER E. H. MATHES, a citizen of the United States, residing at Waterbury, in the county of New Haven and State of Connecticut, have invented a new and useful Improvement in Metal Clock-Dials; and I do hereby declare the following, when taken in connection with the accompanying drawings and the characters of reference marked thereon, to be a full, clear, and exact description of the same, and which said drawings constitute part of this application, and represent a View in front elevation of a clock-dial embod ing my invention.

y invention relates to an improved metal clock-dial of the class commonly known to the trade as circular finished clock-dials from the fact that they are characterized by having their surfaces initially abraded in a series of concentric circles consistin of exceedingly fine and closely placed SCIZLtCIlQCl lines, the object being to produce a photographically printed dial of this character in which the figures are located substantially in the plane of the surface and participate in the characteristics thereof.

With this end in view, my invention consists in a metal clock-dial, characterized by having its surface abraded in a series of concentric circles and its figures photographically printed upon such abraded surface prior to laquering the same, whereby the figures are located in the plane of the finished surface.

In carrying out my invention, the surface of the metal dial 2 is first provided with the so-called circular finish 3, which consists in abrading the surface in a series of fine, concentric circles or scratches so delicate in their character and so closely placed together as to produce a finish giving off radial reflections. Such a circular finish having been applied to the dial in the usual manner, the dial is coated with a sensitized emulsion, for which purpose, I may employ glue, ammonium bichromate, white of egg, and water in the proportions in which the several ingredients are ordinarily used in photo engraving work. The dial is then dried and exposed to light through a so- 1 called high-contrast photographic negative. The dial is now immersed in a bath of water containing a water-soluble dye which operates to stain the entire film with color and therefore its soluble and insoluble portions, portions of it having now become insoluble owing to the action of light upon them through the transparent portions of the negative. A considerable part of the soluble portion of the film will be washed away by this dyeing solution. The dial is now washed in running water for the removal of such soluble portions of the film as remain upon it. It is then dipped in alcohol to remove any water that remains upon it and to facilitate drying it. It is then subjected to the action of a lacquerthinner of standard composition, such as benzol, benzin, amylacetate and fusel oil. This removes the tendency to streaking and staining, and prepares the surface to readily take thefinishing lacquer which is then applied over the entire surface of the dial to protect the metal against tarnishing. The resulting product is a metal clock-dial characterized by the finish imparted to it prior to the photographic printing of the figures upon it. I am thus enabled to produce a dial of far higher and more beautiful finish than can be produced by any process of etching, which eats away the entire surface of the dial, barring the figures, or cats away the figures, barring the remaining surfaces of the dial. In one case, the main surface of the dial is below the figures and in the other case, the figures are below the main surface. In either case, there are two levels, which is characteristic of all etching. In both cases, it is impossible to secure a high finish since etched surfaces cannot be finished. In my process, the printing of the figures upon a pro-finished surface results in but one level, since the dried emulsion constituting the figures has no appreciable thickness. The figures, therefore, are substantially in the plane of the circular finish and partake of the characteristics thereof.

The process herein described, is not claimed herein as it forms the subject matter of, and is claimed in my co-pending application filed May 5, 1919, Serial No. 294,959.

I claim:

As a new article of manufacture, a metal clock-dialcharacterized by having its surface initially abraded in a series of concentric circles and its figures photographically printed upon such abraded surface prior to lacquering the same, whereby the figures are located in the plane of its finished surface.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

GUNTHER E. H. MATHES Witnesses:

J. R. PUTNAM, K. E. MARSHALL. 

